Electrical relay



2 Sheets-Sheet l IP-I fula'on FL'gJ.

INVENTOR CZaPeHOQ SnaUely HIS ATTORNEY 2 Sheets-Sheet 2 c. s SNAVELYELECTRICAL RELAY Filed May 7, 19:57

|IIIIIIIIIA HIS ATTORNEY Fly. 5.

Oct. 31, 1939.

. high speed relay of the type described which can Patented Oct. 31,1939 UNITED STATES PATENT OFFICE ELECTRICAL RELAY Clarence S. Snavely,Pittsburgh, Pa., assigner to The Union Switch &,Signa.l Company,Swissvale, Pa., a corporation of Pennsylvania Application May 7, 1937,Serial No. 141,311

21 Claims.

, application for Letters Patent of the United States, Serial No.31,592, filed by myself and others on July 16, 1935, for Remote controlsystems.

One object of my invention is to provide an improved relay of the typedescribed ot simple, rugged, and compact construction, which willoperate without appreciable wear or change in operatingcharacteristicsover a long period of time and for a very large number ofoperations.

Another object of my invention is to provide a be readily calibrated,and which will operate with sumcient predictable accuracy to permit itto function in timed sequence with a plurality of other similar relaysoperating on close marginal limits without specialA adjustment.

A further' object of my invention is to provide arelay of the typedescribed in which all of the operating parts and contacts are fullyenclosed, but at the same time can be readily seen for purposes ofinspection.

A further object of my invention is to provide a relay of the typedescribed in which the con-v tact assembly comprises a moulded unitwhich can be replaced, when the contacts become unfit for use, by asimilar unit without altering the calibration of the relay.

A still further object of my invention is to provide a relay which lendsitself to ready replacement with another relay when it becomes necessaryto remove the relay from service for inspection or repair.

Other objects and characteristic features of my invention will appear asthe description proceeds.

I shall describe one form of relay embodying my invention and onemounting means therefor, and shall then point out the novel featuresthereof in claims In the accompanying drawings, Fig. 1 is a frontelevational View showing one form of relay embodying my invention, thefront plate of the relay being removed to better illustrate theconstruction of the operating parts of the relay. Fig. 2 is a verticalsectional view of the relay shown in Fig. l taken substantially on theline lI-II of Fig. 1. Fig. 3 is a top plan view of the relay shown inFig. 1. Fig. 4 is a fragmentary right-hand side view of the relay shownin Fig. 3. Fig. 5 is a back view, with the rear cover plate removed,ofthe relay shown in Fig. 1. Fig. 6 is a top plan view of the bracket I6and associated parts forming part of the relay illustrated in thepreceding views. Fig. 7 is a bottom view of the top plate B of the relayas viewed in Fig. 5. Fig. 8 is a diagrammatic view showing by means ofcurves the operating characteristics of the relay illustrated in thepreceding views.

Similar reference characters refer to similar 'l parts in each of theviews.

Referring to the drawings, the relay in the form here shown comprises anelectromagnet A mounted on a top plate B of suitable insulatingmaterial. such for example, as a phenol condensation product. Theelectromagnet A is of the usual and well-known type, and comprises apair of coils l and lxi mounted on spaced parallel cores 2 and 2, theupper ends of which are connected together by a backstrap 3, and thelower ends of which extend downwardly through the top plate B and areprovided on the underside of the top plate with enlarged pole pieces l.The coils l and l are connected in series between two coil connectors 5and al which are secured to the rear side of the top plate B adjacentits opposite ends by means of screws 6, and which extend downwardly pastthe lower side of the top plate for some distance and are providedadjacent their lower ends with holes 'l for a purpose which will appearhereinafter. The screws 6 extend through clearance holes in the coilconnectors 5, and are screwed into threaded inserts moulded into the topplate B. The cores 2 and 2**A may be secured to the top plate B in anyconvenient manner, but as here shown, they are moulded into the topplate.

Secured. to the underside of the top plate B adjacent the rear sidethereof by means of screws l0 is an insulating supporting bracket Ilhaving moulded in, or otherwise secured to, its underside a pair ofauxiliary pole pieces |2-(see Fig. 6). 'Ihe pole pieces I2 extendforwardly toward the front of the relay, and are provided at theirforward ends with ground upper surfaces l2*l1 which comprise pole faces,and which are disposed in spaced parallel relation with respect to thelower or pole faces 4' of the pole pieces 4.

the bracket, and are screwed at their upper ends into threaded insertsmoulded into the top plate. In order to insure the .proper verticallyspaced relation between the two pairs of pole pieces, the underside ofthe top plate B is provided with a pair of laterally spaced dependingbosses l5, the lower surfaces of which are accurately positioned withrespect to the pole faces 4" of the pole pieces 4, and the bracket II isprovided with a pair of upstanding bosses I6 (see Figs. 2 and 5) whichmate with the bosses I 5, and the .upper surfaces of which areaccurately positioned with respect to the pole faces I2B of the polepieces I2. The positioning of the engaging surfaces-of the bosses withrespect to the associated pole pieces can usually be obtained withsufficient accuracy by the moulding of the parts, but these surfacesmay, if desired, be ground after the moulding operation is completed.

Disposed between the two pairs of pole pieces 4 and I2 is a magnetizablearmature I1. This armature is moulded onto or otherwise secured to theupper end of a contactoperatng member I8 of suitable insulatingmaterial, and is adapted to be moved vertically, in response toenergization of the electromagnet A, from a lower position in which itslower surface engages a backstop I I* formed on a forwardly projectingtongue I IJ comprising part of the bracket I I, to an upper position inwhich its upper surface engages a pair of spaced depending front stops2l formed on the underside of the top plate. The contact operatingmember I8 is provided at its upper end with a yoke I8* which straddlesthe tongue III with sufllcient clearance to permit the necessaryvertical movement of the armature, and in its forward surface withaplurality of vertically spaced parallel slots I8t which receive aplurality oi' vertically spaced superposed contact fingers 20intermediate the ends of the fingers. tact fingers 20 are moulded intothe opposite legs of a U-shaped contact support 22 of suitableinsulating material which is secured by means of screws 22Il to theunderside of the top plate B, and the fingers are so disposed thatalternate fingers are located in dierent legs and extend in oppositedirections. Each of the iiexible contact fingers 20 cooperates at itsfree end with an associated fixed front contact member 28 which ismoulded into the leg of the contact support 22 opposite to the leg inwhich the finger is moulded, while the four upper contact fingers alsoeach cooperate with an associated fixed back contact member 24 which islikewise moulded in the leg of the contact support 22 opposite to theleg in which the associated finger is moulded. To decrease contactresistance, the Contact iingers are each provided with contact buttons25 of low resistance conducting material such as silver, which contactbuttons cooperate with contact buttons 28, also of low resistanceconducting material such as silver, provided on the associated x'edcontact members. The contact fingers and lnxed contact members eachextend through the associated legs of the contact support, and areprovided with notched or pierced outer ends to facilitate makingelectrical connections with the fingers and xed contact members. 'I'hescrews 22* which fasten the support 22 to the top plate B extenddownwardly through clearance holes in the top plate, and are screwedinto threaded inserts provided in the upper ends of the legs of theU-shaped contact support.

InV order to permit free straight line vertical movement of the armatureand contact operating The conmember, and at the same time insure thatthe parts will remain in the proper operative relation. the contactoperating member I8 is provided on its forwarli side with verticallyspaced lugs I8 and I8c having aligned openings 18d which slidablyreceive a vertical guide rod 28, and on its rear side with a slotted lugI8 which slidably receives a depending guide pin 29 moulded into thebracket II. The guide rod 28 is mounted at its upper end in an openingIIc provided in the underside of the tongue IIb of the bracket II, andat its lower end in an opening 8| which is provided in the lower end ofthe U-shaped sur port I8. The guide rod 28, after being inserted intothe openings II and 8|, is held in place in these openings by means of ascrew plug 82 which is screwed into the lower end of the opening 8I. Toreduce friction and wear to a minimum, the guide rod 28 and the pin 28will preferably be pro# vided with smooth polished surfaces.

'I'he relay also comprises a back cover plate 88 and a front cover plate84. These cover platesl are clamped against the rear and front sides,respectively, of the top plate B and the U-shaped contact support I8 bymeans of four screws 88, and form with the top plate and the support 22a case which encloses all of the operating parts of the relay. The twoupper screws 85 pass through clearance holes provided in the back coverplate and in the top plate B, and are screwed into threaded insertsmoulded into the front' cover plate, while the two lower screws 8l passthrough clearance holes provided in the back cover plate and in thecontact support 22 and are screwed into threaded inserts moulded intothe front plate. In order to permit reacLv inspection of the operatingparts of the relay without the necessity for removing the cover plates,the front cover plate is formed with a window 86 which is closed by awindow glass 81. The back cover plate 88 is provided in its lorward facewith a recess 88* the opposite sides of which align with recesses 88 and88 formed in the legs of the support 22, and this recess cooperates withthe recesses 88 and 88 to insure that the permanent magnet I8 willremain in proper operative relation with respect to the auxiliary polepieces I2 when the back cover plate is in place on the relay.

The operation of the relay as a whole is as follows: The parts are soproportioned that, when the armature II is approximately midway betweenthe front and back stops, the flexible contact fingers 28 will besubstantially unexed, and the contact buttons 25 on these fingers willbe approximately midway between the contact buttons 28 provided on thecooperating front contact members 28 and back contact members 24. The

parts are further so proportioned that, when the electromagnet A isdeenergized, the flux from the permanent magnet traversing the auxiliarypole pieces I2 and the armature II, together with the weight of thearmature and the contact operating member I8, will exert a suicientbiasing force of the armature to pull it downwardly to the position inwhich it engages the backstop II. and that before the armature has' beenfully moved to the position in which it engages the backstop Il, thecontact buttons 25 on each of the fiexible contact iingers whichcooperates with a fixed back contact member will move into engagementwith the contact button 28 on the associated iixed back contact member.It will be seen. therefore, that the movement of the armature to itslowermost position will cause the centers of anlass those fingers whichcooperate with back contact members to become bowed downwardly at thepoints where they are engaged by the operating member i8, therebyproducing a limited amount 5 of wiping action between the engagingcontact buttons on the iiexible contactiingers and the back contactmembers as the armature moves to its lowermost position, and henceinsuring that, when the armature occupies its lowermost position, thecontact buttons on the fingers will engage the contact buttons on theassociated fixed back contact members with suillcient pressure toprovide an effective low resistance contact. 'I'he downward movement ofthe armature will cause each of the flexible contact fingers which doesnot cooperate with a xed back contact member to continue to. movedownwardly at its free end until the armature reaches its lower, extremeposition. It will be seen therefore from the foregoing that. when thepermanent magnet Il is in place and the parts are properly adjusted, ifthe electromagnet A is deenergized, the front contacts 2li-23 of therelay will be open and the back contacts 2l--2I will be closed.

When the electromagnet A becomes energized, iiux will be forced throughthe electromagnet cores 2 and 2a, the pole pieces I, and the arma-` tureI1, and the parts are so proportioned that this flux will cause theamature i1 to move upwardly in opposition to the bias of the permanentmagnet and the weight of the amature and the contact operating member'Il to its upper extreme position in which it engages the frontstops 2i.This upward movement will cause the contact buttons 2l on the ilexiblecontact fingers to move out of engagement with the contact buttons 28 onthe back contact members and into engagement with the contact buttons 2lon the front contact members, thereby opening the back' contacts y2l-2Iand closing the front contacts -23. The parts are further soproportioned that the contact buttons 2l on the flexible contact fingerswill move into engagement with the contact'buttons 26 on the frontconact members 4g before the armature II reaches its upper extremeposition, and it will be seen. therefore, that the movement of theamature to its upper extreme position will cause thek nexible contactfingers "2l to become bowed upwardly intermediate .their ends, "and willthus. cause a limited amount of wiping action between the contact ,ybuttons and the front contact buttons 2l as the armature completes itsupward movement, as well as insuring a good contact pressure to providean effective low resistance contact.

It should be noted that with the relay ccnstructed in the' manner justdescribed, the ilexible'contact fingers and associated fixed front andback contact members can be moulded into 00 the contact support 22 withsufficient accuracy so that very little, if any, bending of these partsis required to obtain the proper contact adjustments, and that, as aresult, there is substantially no tendency for the contact fingers and'contact members to warp due to these contact members and contactfingers having been given sets in the process of manufacture.Furthermore, there are no built-up" contact spring assemblies whichmight warp or shrink in service, nor are there any insulating bushingsof any kind to break down and cause timing variations or circuitfailures. The front and back contact members are relatively short andrigid so that there is little chance for these parts to warp, and ifthey 75 should warp, the change in the positions of the contact buttonssecured thereto will be so small that the contact adjustment of therelay will not be materially aifected thereby. The flexible contactmembers are held in ilxed positions intermediate their ends by theoperating member Il in such manner that these ilngers are prevented fromwarping between their free ends and the contact operating member, andthe portion of the free ends of these fingers which projects beyond thecontact operating member is relatively short so that, ii' this portionof the iinger shouldvbecome warped, the change in the position of theassociated contact buttons would also be so small that it would producepractically no effect on the contact adiustment of the relay. Inaddition, the adjustment of any one contact is not dependent upon theadjustment of any other contact, so that, if one of the contacts shouldget out of adjustment, it will not affect the adjustment of any of theother contacts. Due to the fact that all of the forces involved inactuating the contacts are in a plane, there are no bearing surfaceswhich carry any heavy loads except the front and back stops for thearmature,

nd the areas andmaterials of these stops are so chosen as to minimizewear. The guide lugs lib, |I,` and il* of the contact operating memberIl do not transmit any forces except any small forces which might existdue to unbalances in .the magnetic circuits or defective mechanicaladjustments. 'I'he forces transmitted by the slots lfof the contactoperating member I8 are small because each bearing surf-ace of theseslots transmits only the force which is necessary to actuate theassociated contact finger in one direction, and the contact ngers haveno initial sets' to compress the back contacts. Also, there are no partswhich can become loosened due to vibration and anect relay operation,nor are there any metal to metal surfaces between the armature and itssupporting means which might become fused due to discharges oflightning, and thus impair or completely prevent the 'operation of therelay.

In a relay o( the type described, it is essential to eliminate contactbounce in so far as it is possible to do so because, when a pair ofcontacts bounce, that is, vibrate with respect to each other when theyare making'contact, the circuit which they are controlling isinterrupted many times in vrapid succession, which causes delay in theoperation of the circuit being controlled. The elimination of contactbounce also minimizes the burning of the contacts due to sparking. Ithas been determinedby tests that the contacts of a relay constructed inaccordance with my invention bounce very much less than the contacts ofrelays heretofore employed for a similar purpose. One reason for this isthat the back contact members, due to their relatively short lengths,are too rigid to vibrate, and any vibration of the contact buttons withrespect to each other must come from the flexible contact iingers, whichfingers are supported intermediate their ends in such a way as to breakup their lengths into two sections which tends to dampen vibration.Also, the forces involved in picking up and releasing the relay arenearly balanced so that the forces tending to move the armature are notmuch greater than the forces tending to retard motion, so that thecontacts do not come together with so sharp a blow. Thisfact can bebetter understood by reference to the curves shown in Fig. 8. Referringto Fig. 8, the curve a represents the force that the armature must forcewhich the exible contact fingers exert on the armature as they arecompressed. The portion of the curve below the stroke axis representsthe back contact compression, and the part above the stroke axisrepresents the front contact compression. Curve e represents the forcewhich the permanent magnet exerts on the amature in order to move thearmature to its lowermost position. Curve c represents the combinationforce exerted by the springs and permanent magnet and is the force whichthe electro-magnet A must exert on the armature II to pickup the relay.Curve d represents the force which the electromagnet A actually exertson the armature I1 when the coils I and Il are supplied with a currentwhich is just equalto the pick-up current for the relay. The differencebetween the curvesdandcistheforcetendingtomovethe' vmotion of theamature. It has been determined by oscillograms that the current owingin the coils I and I* is approximately equal to the pickup currentduring the motion of the armature, l

so that the difference between curves d and c 'approximately representsthe acceleratingforce of the armature during the motion of the armature.It will be seen, thereforepthat it is possible to control theaccelerating force by controlling the shape of the curve d. This is donein the present case by controlling the cross-sectional area'of the corestructure of the electromagnet and the area of the pole pieces. Inthisway the bounce is minimized when the relay picks up.

It should be particularly pointed out that. while the relay as shown isprovided with eight front contacts and four back contacts, my inventionis not limited to this particular contact combination, and any othercontact combination may be provided which is necessary for anyparticular operating condition.

- As has been pointed out hereinbefore, a relay embodying my inventionis intended for use in centralized tramc controlling systems forrailroads wherein large numbers of relays are employed, and it isnecessary, in order. to avoid trafiic delays, to be able to quicklyremove any relay from service and replace it with another relay.

To permit this to be done with relays embodying my invention, I providea pair of relay connectors C1 and C2, one for making connection with theouter ends of the flexible contact ngers 'and xed contact members of therelay on each side of the relay. These connectors are similar, exceptfor the fact that one is a right-hand connector and the other aleft-hand connector, and it is believed, therefore, that a descriptionof one connector will suillce for both. Referring to the connector C1shown in Figs. l, 3, and 4, this connector comprises a plurality ofconducting strips 43 moulded into a block 44 of insulating material invertically spaced parallel relation. The strips 43 extend through theblock 44 from the front end thereof to the back end, and have theirfront ends disposed in parallel slots 45 which are spaced apart the samedistance as the outer ends of the contact ilngers and xed contactmembers of the relay, and which are of such height exert to compress thecontacts ss well as the vertically that the xed contact members andcontact ngers can be slipped into these slots above the ends of theconducting strips 4I with a sliding tit. To facilitate slipping thecontact fingers and fixed contact members into place above the strip.the portions of the conducting strips which are disposed in the'slots 45are curved upwardly and then downwardly in such manner that the forwardends of the strips bear against the bottom of the slots with sometension. With this arrangement when the lingers,

and fixed contact members are slipped into piece in the slots 4l thebowed portions of the oonducting strips become flattened somewhat, thusinsuring a good contact between the fingers and the associated strips.The upper end of the connector C1 is provided at its forward side with anotch 44 which when the connectorI is in proper operative relation withrespect to the relay, receives the projecting end ofthe top plate and alaterally projecting portion '22" which is formed on the contact support22 below the top Plek.

Moulded into the-upper parto! the connector at the rear side of thisnotch is a round .post 4l which projects forwardly through thepreviously described hole 1 in the coil connector 5 and an aligned hole41 formed in the laterally projecting portion 22h, and is provided atits forward end with the threaded portion for the reception of a nut 4lby means of which the relay and connector may be secured in properoperative relation. 'I'he post 46 is also provided at the forward sideof the connector with a shoulder 4ll which cooperates with the rear faceof the coil connector I in such manner that, when the nut 4I istightened, the shoulder 48 will be forced into contact with theconnector I with considerable presure, thus insuring good electricalcontact between the post 48 and the coil connector l. 'Ihe rear end ofthe post 4t extends beyond the rear face of the block for some distanceto enablel a circuit wire to be soldered thereto. The outer surface ofthe connector is provided with a vertical groove for the reception of amounting bracket 49, to which the connector is adapted to be secured bymeans ot suitable screws Il.

In use, the two relay connectors Cl and C' are secured to two of themounting brackets 4I directly opposite each other, these mountingbrackets being spaced apart the proper distance to permit a relay to beslipped into .operative engagement with the connectors. The circuitwires are then permanently secured to the rearwardly projecting portionsofthe strips 43 and the post 46. The relay ls then slipped into-operative lelation with respect to the connectors and is Vlocked inplace by means of the nuts 4l. When it becomes necessary to replace arelay, the nuts 4B are removed and the relay is slid outwardly out ofoperative engagement with the connectors and a new relay is slid' intoplace, after which the nuts 4l are again tightened. It will be seen,therefore, that with the relay constructed in accordance with myinvention, and cooperating with connectors embodying my invention, inthe manner shown in Figs. l and 3 the relay may be quickly removed andreplaced with a similar relay, thus insuring minimum tramc delays. Itwill also be seen thatthe connectors serve not only as a, means forproviding electrical connection with, but also as a, convenient `meansfor supporting, a relay in a manner which permits a, large number ofrelays to be conveniently mounted in a relatively small space.

Although I have herein shown and described 7s only one form of relayand' one form of connectors embodying my invention, it is understoodthat various changes and modifications may be made therein within thescope of the appended claims without departing' from the spirit andscope of my invention.

Having thus described my invention, what I claim is:

1. An electrical relay comprising an insulating top plate, anelectromagnet mounted on said top plate and including a, pair of polepieces which are disposed on the underside of said'top plate, a pair ofconstantly magnetized pole pieces secured to the underside of said topplate and disposed in spaced parallel relation with respect to the polepieces of said electromagnet, an armature slidably supported forstraight line movement between said two pairs of pole pieces, aninsulating member secured to said top plate and having moulded thereinmovable contact iingers and iixed contact fingers which cooperate withsaid movable contact fingers, and means for operatively connecting saidmovable contact fingers with said armature.

2. An electrical relay comprising an insulating top plate, anelectromagnet mounted on said top y plate and including a pair of polepieces which are disposed on the underside of said top plate, a pair ofconstantly magnetized pole pieces secured to the underside of said topplate and disposed in spaced parallel relation with respect to the polepieces of said electromagnet, an armature slidably supported forstraight line movement between said two pairs of pole pieces, aninsulating member secured to said top plate and having moulded thereinin superposed relation cooperating movable contact fingers and iixedcontact members, and means for actuating said movable contact ingersconnected with said fingers and with said armature. y

3. An electrical relay comprising an amature, a contact operating membersecured to said armature and comprising means i'or slidably supportingsaid armature for straight line movement between two extreme positions,means including a permanent magnet for normally biasing said armature toone extreme position, electromagnetic means eiectlve when energized formoving said amature to itsother extreme position, a plurality` ofilexlble contact lingers rigidly supported at one end' and operativelyconnected intermediate their ends with said contact operating member,and iixed contact members cooperating with said ngers at their freeends.

4. An electrical relay comprising an insulating top plate, a pair ofparallel cores mounted in said top plate` and provided on the undersideof said top plate with a iirst pair of pole pieces,` a backstrapconnecting said cores at their upper ends, windings mounted on saidcores, a second pair of pole pieces secured to the underside of said topplate in parallel spaced relation with respect tothe pole pieces of saidrst pair, a permanent magnet for magnetizing the polepieces of saidsecondA pair, an armature slidably supported for straight line movementbetween said two pairs of pole pieces, a contact supporting membersecured to said top plate, cooperating movable contact fingers and fixedcontact members moulded ln said contact supporting member, and meanssecured to said armature and engaging said movable contact fingersintermediate vtheir ends for actuating said movable contact 'HiV inresponse to the movement of said armature between said two pairs of polepieces.

5. In an electrical relay, the combination with an armature, of acontact operating member secured to said armature and comprising meansfor slidably supporting said armature for straight line movement betweentwo extreme positions, said contact operating member being provided witha plurality of spaced slots, a plurality oi flexible contact iingersrigidly supported at one end and iittng in said' slots intermediatetheir ends in such manner that said lingers are unstressed when saidarmature is approximately midway between its two extreme positions, andiixed contact members cooperating with .said iixed contact fingers attheir free ends to form contacts which are operated by the movement ofsaid armature between its two extreme positions.

6. vIn an electrical relay, the combination with an armature, of acontact operating member secured to said armature and' comprising means`for slidably supporting said armature for straight line movementbetween two extreme positions, said contact operating member beingprovided with a plurality of spaced slots, a plurality oi will engagesaid front contact members but that when said armature is moved Vto itsother extreme position said ilexible contact finger will engage saidback contact members.

'1. An electrical relay comprising an insulating top plate, anelectromagnet mounted on said top plate and including a pair of polepieces which are disposed on the underside oi' said top plate, a pair ofconstantly magnetized pole pieces secured to the underside of said topplate and disposed in spaced parallel relation with respect to thepole'pieces of said electromagnet, a U-shaped contact support secured tothe underside oi said in superposed relation movable contact ngers andcooperating fixed contact members, a'contact operating member slidablysupported for vertical movement and provided with slots which receivesaid ilngers, an armature secured to said contact operating member anddisposed between said two pairs of pole pieces, a back plate clampedagainst the rear side of said top plate and said contact support, and airont plate clamped against the front side of' sid top plate and saidcontact support and provided with a window closed by a window glassthrough which the operating parts of said relay vmay be viewed.

8. An electrical relay comprising an insulating top plate, anelectromagnet mounted on said top plate and provided on the underside ofsaid top plate with a pair of pole pieces, a pair oi.' con- `top plateand having moulded in the legs thereof derside of said top plateandprovided with pole faces disposed in spaced parallel relation withrespect to the pole faces of the pole pieces of said electromagnet, anarmature slidably supported for straight line movement between said twopairs of pole pieces, a contact operating member secured to said amatureand comprising part of the means for slidably supporting said amature,

said contact operating means being provided with a plurality of spacedslots, an insulating contact l supporting member secured to theunderside of l'io said top plate and having moulded therein a pluralityof exible contact fingers which are rigidly supported at their ends insaid member and which nt in said slots intermediate their ends in suchmanner that said fingers are unilexed when said armature isapproximately midway between said two pairs of pole pieces, and fixedcontact members moulded in said insulating contact supporting member andcooperating with the free ends of said exible contact fingers.

9. An electrical relay comprising an insulating .top plate; `a pair ofparallel cores mounted in said top plate and provided on the undersideof said top platev with a first pair of pole pieces, a backstrapconnecting said cores at their upper ends, windings mounted on saidcores, a second pair of pole 'pieces lsecured tothe underside of saidtop plate and disposed with their pole faces in parallel spaced relationwith respect to the pole faces of said ilrst pair, means for magnetizingsaid second pair of pole pieces, an armature slidably supported forstraight line movement between said two pairs of pole pieces, a U-shapedinsulating contact supporting member secured to the underside of saidtop plate and having moulded therein flexible contact fingers and ilxedcontact members the outer ends of which project through the less of saidsupporting member to facilitate makingelectrical contact therewith .andthe inner ends of which cooperate with each other to form contacts,means secured to said armature and connected with said flexible contactfingers intermediate their ends for actuating said flexible contactfingers, a back plate secured to one side of said top plate and one sideof said contact supporting member, and a front plate including atransparent member secured to the other side of said top plate and theother side ofv said contact supporting member, whereby the contacts andall of the movable parts of said relay are enclosed within the caseformed by said top plate, said U-shaped contact supporting member andsaid front and back plates but are open to inspection through saidtransparent member.

i0. An electrical relay comprising an insulating top plate, a pair ofparallel cores mounted in said top plate and provided on the imdersideof said top plate with a nrst. pair of pole pieces, a backstrapconnecting said cores at their upper ends, windings mounted on saidcores, a second pair of pole pieces secured to the underside of said topplate and disposed with their pole faces in parallel spaced relationwith respect to the pole faces of said first pair. means for magnetizingsaid second pair of pole pieces. an armature slidably supported forstraight line movement between said two pairs of pole pieces, a contactoperating member secured to said armature and forming part ofthe meansfor slidably supporting said armature, said contact operating memberbeing provided with a plurality of vertically spaced slots, a pluralityoi flexible contact fingers rigidly supported at one'end and fitting insaid slots intermediate their ends in such manner that sam fingers areunexed when said armature is approximately midway between said two pairsof pole pieces, and front and back contact members cooperating with saidflexible contact ngers at their free ends in such manner that when saidarmature is moved toward the pole pieces of said ilrst pair saidflexible contact fingers will engage said front contact members but thatwhen said armature is moved toward the -pole pieces of said second pairsaid flexible contact i'ingers will engage said back contact member.

l1. An electrical relay comprising a top plate, an electromagnet mountedon said top plate and provided on the underside of said top plate with afirst pair o! Dole pieces, a second pair of pole pieces secured to theunderside of said tcp plate and disposed with their pole faces in spacedparallel relation with respect to the pole faces of said first pair, aU-shaped member of moulded insulating material having opposed recessesformed in the rear side thereof, a permanent magnet fitting in saidrecesses, and having its ends connected with the pole pieces of saidsecond pair, a back plate clamped against the rearside of said top plateand said U-shaped member and having in its inner face a recess whichpartly receives said permanent magnet and which assists in holding saidpermanent magnet in place, a combined contact operating and armaturesupporting member slidably supported between the legs of said U-shapedmember and provided at its upper end with an armature which cooperateswith said two pairs of pole pieces to move said contact operating memberto one extreme position, or another according as said electromagnet isenergized or deenergized, flexible contact nngers moulded in the legs ofsaid Ur-shaped mexn-v ber in superposed relation in such manner thatalternate lingers are disposed in different legs and are operativelyconnected intermediate their ends with said contact operating member,iixed contact members moulded in the legs of said U- shaped member andcooperating with said ilexible contact fingers, said fixed contactmember and movable contact fingers being provided with portions whichproject through the associated legs of said U-shaped member to providemeans for making electrical connections with said contact fingers andsaid contact members, and a front plate clamped against the front sideof said top plate and said U-shaped member and including a transparentmember through which said armature and the contacts of said relay may beviewed.

12. An electrical relay comprising a top plate. an electromagnet mountedon said top plate and provided on the underside of said topplate with ailrst pair of pole pieces, a second pair of pole pieces secured to theunderside of said top plate and disposed with their pole faces in spacedparallel relation with respect to the pole faces oi said first pair, aU-shaped member of moulded insulating material having opposed recessesformed in the rear side thereof, a permanent magnet fitting in saidrecesses and having its ends connected with the pole pieces of saidsecond pair, a back plate clamped against the rear side of said topplate and said U-shaped member and having in its inner face a recesswhich partly receives said permanent magnet and which assists in holdingsaid permanent magnet in place, a combined contact operating andarmature supporting member slidably supported between the legs of saidU-shaped member and provided at its upper end with an armature whichcooperates with said two pairs of pole pieces to move said contactoperating member to one extreme position or another according as saidelectromagnet is energized or deenergized, cooperating xed contactmembers and flexible contact ilngers moulded in the opposite legs ofsaid U-shaped member, said flexible contact ilngers being operativelyconnected intermediate their ends with said contact operating member,

ss and provided on the arr/anso and a front plate clamped against thefront side of said top plate and saidU-shaped member and including awindow glass through which the operating parts of said relay may beviewed.

13. An electrical relay comprising a moulded top plate of insulatingmaterial, an electromagnet having its cores moulded into said top plateand provided on the underside of said top plate with a pair of polepieces, a bracket of moulded insulating material secured to theunderside of said topl plate, a pair of auxiliary pole pieces mouldedinto said bracket and provided with pole faces which are adapted to bedisposed in spaced parallel relation pole pieces of said electromagnet,said top plate being provided on its underside with integral dependingbosses having faces which are accurately positioned with respect to thepole faces of the electromagnet pole pieces and said bracket havingintegral upstanding bosses which engage the bosses on said top plate andthe faces of which are accurately positioned with respect to the polefaces of said permanent magnet cores, whereby when the cooperating facesof Asaid bosses are engaging each other an accurate spacing is providedbetween said two pairs of pole pieces, means for magnetizing saidauxiliary pole pieces, an armature mounted for straight line movementbetween said two pairs of pole pieces, front stops moulded on theunderside of said top plate for limiting the movement of said armaturetoward the pole piece of said electromagnet, and a backstcp provided onsaid bracket to limit the movement of said amature toward said auxiliarypole pieces.

14. An electrical relay comprising a moulded top plate of insulatingmateriaL'an electromagnet having its cores moulded into said top plateand provided on the underside of said top plate with a pair of polepieces, a bracket oi moulded insulating material secured to theunderside of said top plate, a pair of auxiliary pole pieces mouldedinto said bracket and provided 4with pole faces which are adapted to bedisposed in spaced parallel relation with respectto the pole faces ofthe pole pieces of said electromagnet, said top plate being provided onits underside with integral depending bosses having faces which areaccurately positioned of the electromagnet pole pieces and said brackethaving integral vupstanding bosses which engage the bosses`on said topplate yand the faces of which are accurately positioned with respect tothe pole faces of said permanent magnet cores, whereby wh'en thecooperatingl faces of said bosses are engaging each other an accuratespec-'- ing is provided between said two pairs of pole pieces, means formagnetizing said auxiliary pole pieces, and an armature mounted forstraight line movement between said two pairs of pole pieces. y

15. An electrical relay comprising a moulded top plate of insulatingmaterial, an electromagnet having its cores moulded into said top plateunderside of said top plate with a pair of pole pieces, a bracket ofmoulded insulating material secured to the underside of said top plate,a pair of auxiliary pole pieces i moulded into saidbracket and providedwith pole 0 faces which are adapted to be disposed in spaced parallelrelation with respect to the pole faces of the pole pieces of saidelectromagnet, said top plate being provided on its underside withintegral depending bosses having faces which are i@ accuratelypositioned with respect to the pole with respect to the pole faces ofthe with respect to the pole faces faces of the electromagnet polepieces and saidy bracket having integral upstanding bosses which engagethe bosses on said top plate and the faces of which are accuratelypositioned with respect to the pole faces of said permanent magnetcores, whereby when the cooperating faces of said bosses are engagingeach other an accurate spacing is provided between said two pairs' ofpole pieces, means for magnetizing said auxiliary pole pieces. anarmature mounted for straight line movement between said two pairs ofpole pieces, and contacts controlled by said armature.

16. An electrical relay comprising an insulating top plate, anelectromagnet mounted on said top plate and provided on the underside ofsaid top plate with a pair of pole pieces, an insulating bracket securedto the underside of said top plate and provided with a depending guidepin and with a tongue, a pair of auxiliary pole pieces secured to saidbracket on opposite sides of said tongue and provided with pole facesdisposed in spaced parallel relation with respect to the pole faces ofthe pole pieces of said electromagnet, means for magnetizing saidauxiliary pole pieces, a U-shaped member secured to the underside ofsaid top plate, a guide rod extending parallel to said guide pin andmounted at its upper end in said tongue and at its lower end in said U-shaped member, a contact operating member provided with a yoke whichstraddles said tongue with clearance between said auxiliary pole piecesand with a pair of spaced lugs having aligned openings which slidablyreceive said guide rod and with a slotted lug which slidably receivessaid guide pin, and an armathre secured intermediate its ends to theyoke of said contact operating member and having its ends disposedbetween said two pairs of pole pieces.

17. An electrical relay comprising a U-shaped contact support having aplurality of superposed exible contact fingers moulded in its oppositelegs-in parallel spaced relation in'such manner that alternate fingersextend in opposite directions, fixed contact members moulded in the legsof said support and cooperating with said fingers at their free ends, aguide rod extending at right angles to said fingers in spaced relationthereto intermediate the legs of said support. la guide pin extendingparallel to said rod on the opposite side of said fingers from said rod,a conv tact operating member of insulating material provided with spacedslots which receive said contact fingers intermediate their ends andwith a pair of sp'aced lugs having aligned apertures which slidablyreceive said guide rod and with a slotted lug which slidably receivessaid guide pin, whereby said operating member is guided to move indirections to open and close the contacts formed by said fingers andsaid xed contact members, and electromagnetic means for actuating saidoperating member between its contact operating positions. I

18. An electrical relay comprising a U-shaped contact support having aplurality of superposed flexible Contact fingers moulded in its oppositelegs in parallel spaced relation in such manner that alternate fingersextend in opposite directions, fixed contact members moulded in the legsof said support and cooperating with said fingers at their free ends, aguide rod extending at right angles to said fingers in spaced relationthereto intermediate the legs of said support, a guide pin extendingparallel to saidv rod on the opposite side of said fingers from saidrod, a contact operating member of insulating material provided withspaced slots which receive said contact iingers intermediate their endsand with a pair of spaced lugs having aligned apertures which slidablyreceive said guide rod and with a slotted lug which slidably receivessaid guide pin, whereby saidv operating member is guided to move indirections to open and close the contacts formed by said fingers andsaid fixed contact members, means including an amature secured to saidoperating member and a permanent magnet cooperating withvsaid amaturetor biasing said operating member to one contact operating position, andmeans including said armature and an electromagnet cooperating with saidarmature for moving said operating member in opposition to the bias ofsaid permanent magnet to another contact operating position.

19. An electrical relay comprising a U-shaped contact support having aplurality oi superposed flexible contact ingers moulded in its oppositelegs in parallel spaced relation in such manner that alternate iingersextend in opposite directions, iixed contact members moulded in the legsof said support and cooperating with said iingers at their free ends, aguide rod extending at right angles to said fingers in spaced relationthereto intermediate the legs of said support, a guide pin extendingparallel to said rod on the opposite side of said iingers from said rod,a contact operating member of insulating material provided with spacedslots which receive seid contact iingers intermediate their ends andwith apair of spaced lugs having aligned apertures which slidablyreceive said guide rod and.. with a slotted lug which slidably receivessaid guide pin, whereby said operating member is guided to move indirections to open and close the contacts formed by said fingers andsaid fixed contact members, an armature secured to said con tactoperating member, and means including an electromagnet and a permanentmagnet mounted on a top plate secured to the upper end of said U-shapedbracket and cooperating with said armature for moving said contactoperating member between two contact operating positions.

20. An electrical relay comprising a U-shaped t contact support having aplurality of superposed 2l. Switching means comprising a U-shaped g5insulating contact support having a plurality of ilexible contactfingers moulded in its opposite legs in parallel spaced relation insuchy manner that alternate fingers extend in opposite directions, xedcontact members moulded in the legs 30 of said support and cooperatingwith said fingers at their free ends. and operating means for saidflexible tlngers comprising an insulating member slidably supported forstraight line movement and provided with slots which receive said fiexi-35 ble fingers intermediate-their ends.

CLARENCE S. SNAVELY.

